Here we see details of the final panel in the Villa of the Mysteries. The newly initiated woman is being groomed for her divine "marriage." The cupid on the left is holding a mirror.
Though not specifically writing about the Dionysiac cult, a good description of the behavior of disciples of Dionysus was provided by the Apostle Paul in his letter to the Galatians (5:19-21). Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness, idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies, envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God.
This sort of lawlessness was disdained by those in authority in Rome. Though not desiring to destroy the Dionysiac cult entirely, the Senate passed laws to curtail the extremes of their behavior during their "worship" services, which initially occurred 3 times per year, then 5 times per month later.